@@ -233,35 +233,52 @@ fn attrs_and_tokens_to_token_trees(
233233
234234 // Insert inner attribute tokens.
235235 if !inner_attrs. is_empty ( ) {
236- let mut found = false ;
237- // Check the last two trees (to account for a trailing semi)
238- for tree in res. iter_mut ( ) . rev ( ) . take ( 2 ) {
239- if let TokenTree :: Delimited ( span, spacing, delim, delim_tokens) = tree {
240- // Inner attributes are only supported on extern blocks, functions,
241- // impls, and modules. All of these have their inner attributes
242- // placed at the beginning of the rightmost outermost braced group:
243- // e.g. fn foo() { #![my_attr] }
244- //
245- // Therefore, we can insert them back into the right location
246- // without needing to do any extra position tracking.
247- //
248- // Note: Outline modules are an exception - they can
249- // have attributes like `#![my_attr]` at the start of a file.
250- // Support for custom attributes in this position is not
251- // properly implemented - we always synthesize fake tokens,
252- // so we never reach this code.
236+ let found = insert_inner_attrs ( inner_attrs, res) ;
237+ assert ! ( found, "Failed to find trailing delimited group in: {res:?}" ) ;
238+ }
239+ 240+ // Inner attributes are only supported on blocks, functions, impls, and
241+ // modules. All of these have their inner attributes placed at the
242+ // beginning of the rightmost outermost braced group:
243+ // e.g. `fn foo() { #![my_attr] }`. (Note: the braces may be within
244+ // invisible delimiters.)
245+ //
246+ // Therefore, we can insert them back into the right location without
247+ // needing to do any extra position tracking.
248+ //
249+ // Note: Outline modules are an exception - they can have attributes like
250+ // `#![my_attr]` at the start of a file. Support for custom attributes in
251+ // this position is not properly implemented - we always synthesize fake
252+ // tokens, so we never reach this code.
253+ fn insert_inner_attrs ( inner_attrs : & [ Attribute ] , tts : & mut Vec < TokenTree > ) -> bool {
254+ for tree in tts. iter_mut ( ) . rev ( ) {
255+ if let TokenTree :: Delimited ( span, spacing, Delimiter :: Brace , stream) = tree {
256+ // Found it: the rightmost, outermost braced group.
253257 let mut tts = vec ! [ ] ;
254258 for inner_attr in inner_attrs {
255259 tts. extend ( inner_attr. token_trees ( ) ) ;
256260 }
257- tts. extend ( delim_tokens . 0 . iter ( ) . cloned ( ) ) ;
261+ tts. extend ( stream . 0 . iter ( ) . cloned ( ) ) ;
258262 let stream = TokenStream :: new ( tts) ;
259- * tree = TokenTree :: Delimited ( * span, * spacing, * delim, stream) ;
260- found = true ;
261- break ;
263+ * tree = TokenTree :: Delimited ( * span, * spacing, Delimiter :: Brace , stream) ;
264+ return true ;
265+ } else if let TokenTree :: Delimited ( span, spacing, Delimiter :: Invisible ( src) , stream) =
266+ tree
267+ {
268+ // Recurse inside invisible delimiters.
269+ let mut vec: Vec < _ > = stream. iter ( ) . cloned ( ) . collect ( ) ;
270+ if insert_inner_attrs ( inner_attrs, & mut vec) {
271+ * tree = TokenTree :: Delimited (
272+ * span,
273+ * spacing,
274+ Delimiter :: Invisible ( * src) ,
275+ TokenStream :: new ( vec) ,
276+ ) ;
277+ return true ;
278+ }
262279 }
263280 }
264- assert ! ( found , "Failed to find trailing delimited group in: {res:?}" ) ;
281+ false
265282 }
266283}
267284
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